As program controlled switching stations have evolved, a number of custom calling features have been developed, including incoming calling line identification. This feature displays the calling party's number to a display unit, allowing selective acceptance of certain calls while other calls are either not answered or routed to a message centre.
Sample features for call display units on the market include:
Memory to store information about the previous incoming calls, including those that were not answered, such as calling party number, time and date; PA1 Display, scroll and delete functions to remove the information stored in memory; PA1 The date and time of each call, answered or unanswered; and PA1 The number of times that a particular number called.
These units typically require the user to walk over and look at the display in order to determine the number of the calling party. As well, customers usually remember only a few numbers that they frequently call so they often cannot identify the party simply from the calling number on the display.
A number of solutions have been proposed.
U.S. Pat. Nos. 5,007,076, 4,922,490, and 4,899,358 to Blakley each disclose a caller identification system at a telephone switch that stores at the switch text representations entered through the called party's telephone keypad of the names corresponding to the numbers of frequent calling parties. When the number of a calling party matches one of the numbers for which a name has been stored then the system converts the name from text to speech and speaks it to the called party through the called party's telephone in the blank time between rings.
U.S. Pat. No. 4,894,861 to Fujioka discloses a single unit integrating a telephone with a call display, speech memory, a text to speech generator and a speaker. The unit stores text representations entered at the called party's telephone keypad of calling party names corresponding to their numbers, converts them to speech when there is a match with a calling party number and speaks them through the speaker.
The use of the keypad for entering text requires the user to understand which numbers or combination of numbers correspond to a given letter and to know the spelling of the calling party's name. Alternatively, a full keyboard can be used, but this would require a custom telephone for the Blakley system or would add to the expense and size of the Fujioka unit.
Speech generators typically have poor sound quality or are relatively expensive. They also have a limited number of `voices` from which to select and can have difficulty pronouncing all but the simplest of names.
Existing units do not provide for remote access of stored calling party information. Those with display only capability cannot interface with remote telephones to provide information. Fujioka cannot open the telephone line and therefore cannot accept a telephone call without a user being at the unit.